Light "click" or "snap" or "clunk" when pressing down hard on pedals

Hey guys. A few weeks ago I started noticing a click or snap that can be felt as much as heard when I push down on the pedals really hard (pushing up a steep hill, accelerating hard from a stop, etc).

I took my bike in for a tuneup, because it was due anyway, and they were going to replace the chain. I told them about the noise/feel and they said they'd check it out.

Well, long story short, those bastards didn't do a damn thing in the tuneup other than throw a new chain on it, lube the cables, clean the bike and **** up a previously fine derailleur adjustment. I won't be returning there for service, but that's a different story.

Anyway, the click/clunk is still there. I started to think it was the pedals wearing out, so I swapped them with a pair off my hybrid bike, and it's still doing it.

Ideas? Can a worn rear cassette do this? Chain ring? The previously mentioned shop didn't seem to think the bottom bracket was the problem, but apparently they are hacks... I don't even really know how to describe it, other than when I push down on the pedal hard, it goes "click" and I feel something displace slightly. Feels crappy; I hate it. I'm on a tight budge right now so I can't throw parts at the thing without knowing what the problem is. It's making me not want to ride it

EDIT: forgot to mention that the longer I ride the bike, the less it does it. It's like it's worst when the bike is "cold" but then when I ride for a while and "warm up the bike" it pretty much goes away. WTF?

I just fixed a clunking problem on my bike today. It was the opposite though. It seemed to get a little worse near the end of my ride. It was most noticeable when I was coasting/freewheeling. It turns out the problem was in the hub. One of the Pawls was sticking. I took it apart, cleaned the Pawls, regreased them and the sound is gone for now.

Last year I had a clicking that I thought was my bottom bracket because it was only noticeable when I was pushing hard on the pedals. I replaced the BB30 bearings with ceramic ones. That didn't work. So I loctited the bearings into place - that didn't work. Finally I figured out that it was my SRAM XG-1080 cassette. The metal tube that passes through the center of it broke loose. As it shifted under hard pedaling it clicked and clunked. I changed it to an XG-1099 cassette and the noises never came back.

What kind of BB and crank do you have on this bike? This is a common sound from sqaure taper cranksets as well as a few others. Mostly the sound is "creaking" between the crank arm and the bottom bracket spindle. Usually taking the crank off, cleaning it and putting it back on "dry" gets rid of the problem.

I've had the same issue.. and seen it a few other times on bikes I've worked on for friends and 3 outa 4 times it was the crank arm loose,.. or was loose for a long time and the splines got tweaked. One Sram/Truvativ and 2 were Raceface. All very similar "feel". Just a minor 'click" feel when pedaling harder..

even after resetting they still did it (but much less) until I replaced the crank arm. Try taking cranks apart and cleaning really good,.. reassemble and see it it gets better...
another easy ay to tell if it's the cranks is to just flip the bike over on the floor or other smooth solid surface, take the cranks in your hand and bare down hard in opposite directions.. turn the cranks 180 degrees and do it again.. see if you can feel/hear it. If not move on to one of the other suggestions stated above by others...

Square taper like was stated above often has the same issue...

Both the Racefaces were because they put chain guides mounted behind the bb cup and over extended the whole bottom bracket causing the crank arm to not seat 100% on the spindle, and the Sram was mine and just being lazy and forgetting to tighten it after I noticed the slightly loose crank arm on the first ride it happened,.. crap got in there and cause me not to be able to seat it properly and I just kept beating on in like a dumb ass (is was my back up/loaner bike)